Like a couple of mechanics hired to tune up a balky race car, it’s been obvious in recent games what Kevin Wilson and Ryan Day have done to enhance the Ohio State offense this season.

They’ve added a teethier passing gear.

Now, Wilson, the offensive coordinator, and Day, the quarterbacks coach, testified that in their first year at OSU they’ve simply honed the parts on hand in order to give their driver, fourth-year starting quarterback J.T. Barrett, a peppier ride. Seven games in, the Buckeyes, who had a bye Saturday, lead the Big Ten in scoring (47.3-point average), total offense (577.3 yards) and passing (326.7 yards).

Indeed, since a loss to Oklahoma in week two they have used the past five games as test tracks for the passing game.

“When you look at the film you have to look at it through the eyes of what your players can do, and then make sure you’re picking the right things,” said Day, whose last two seasons were in the NFL with Philadelphia and San Francisco. “Like coach (Urban) Meyer said when we got here, ‘If you know a play, we probably have run it.’ And he’s right. That playbook is this big (hands a foot apart). So our challenge has been finding the right ones that fit our personnel.”

As for the personnel, there’s been some fine tuning. For example, take one of the several things that Barrett said Day has helped him with to create a more potent over-the-middle attack.

“One-inching the underneath defenders,” Barrett said, meaning making throws just an inch or so over the maximum reach of a leaping linebacker’s hand. “That takes a lot of practice. ... Then there’s the timing of it. You can’t be late on those throws. … And you’ve got to be confident and just rip the ball in there.”

The biggest difference has been the willingness to attack the middle of the field, something the Buckeyes lacked against Oklahoma. Anyone paying attention lately, said Stanley Jackson — former Ohio State quarterback who does analysis for the Big Ten Network and WXZX (105.7 FM) — can see that.

“The first thing that jumps off the page, if you go back to the year when Florida (coached by Meyer) beat up Ohio State in the (2006) national championship game, the most prominent route they ran in that game was the shallow cross,” Jackson said.

That’s wide receivers, tight ends or backs running routes across the middle of the field in the short and intermediate zones, sometimes criss-crossing to complicate matters for the defense. Whether it’s been Barrett hitting one of the crossers on the run or, for example, hitting Johnnie Dixon on a sit-down route over the middle behind the crossers, it has been effective.

“That’s an effective wrinkle,” Jackson said. “They also are using their tight ends in a more effective way.

“But the most important point might be this: After Tom Herman (offensive coordinator of the 2014 national championship team and now head coach at Texas) left, it seemed like the past two years the Buckeyes had a game plan, and no matter what the defense did, they stuck to that game plan with no adjustments in the game. The in-game adjustments have improved significantly.”

Wilson and Day sit side by side in the press box in the game and talk constantly. But they’re not just pulling plays out of a sack; they’re reaching for contingencies practiced repeatedly during the week.

“One, we’re getting some great communication during the week from coach Meyer of things he wants to see or why,” Wilson said. “Ryan is doing a great job of mixing up some pass thoughts, and I’ve got a little idea of tempo and going fast.

“Now again, there’s always going to be bumps in the road, you don’t block it well, or you don’t guess right and call a bad play and get behind the chains (third and long). But right now — we don’t have all the answers, but we’re working together very well.”

As Day pointed out, though, the Buckeyes ripped through the lesser opponents last year, then bogged down against the better defenses, just as they did against Oklahoma six weeks ago. It wasn’t just the play calling, but at times the pass protection and the disappearing receivers that were the problem.

The next true test comes Saturday.

“Now we’ve got to go play well,” Day said. “We’ve got to go play against Penn State and show that we have taken this big step.”